Purging The Headers; Adding Antifreeze /Inhibitors - Kensa Group Kensa Heat Pumps P250X Manual

5.1.2 Purging the headers

Once the ground arrays have been purged of air it is important that the header pipe is also purged. This
should be done by connecting the purge points together on each array manifold in turn using suitable
pipe to create a loop. The purging should then be carried out from the header manifold following the
same purging procedure as for the ground arrays.
To ensure all the air is removed it is advised that when the headers have been purged the ground arrays
are purged again and automatic air vents are connected at high points where air can collect. After the air
has been removed it is advisable that before the antifreeze is added the system is leak tested to BS805
Section 11.3.3.4. (See 5.1.3), if this didn't occur when the ground arrays were installed.

5.1.3 Adding antifreeze /inhibitors

The antifreeze provides protection to the heat pump (and contains an inhibitor and anti-bacterial agents)
by preventing the circulating ground fluid from freezing in the heat exchanger. If not added in sufficient
quantities the heat pump can freeze and cease working. All antifreeze provided with the order should be
added and it is recommended that the quantity is roughly divided between the number of arrays. This
amount of antifreeze is the minimum required for a standard system (at least 22% concentration by vol-
ume , Refractive index 1.356). If the heat pump and manifold are a distance apart and header manifolds
are present this quantity of antifreeze provided may need to be increased. Please contact Kensa for further
details.
It is very important to purge all the air from the system before adding the antifreeze as it is very difficult
to remove the air with the antifreeze in the system due to the higher viscosity of the mixture.
Once the purging of all the air within the arrays and heat pump has been completed the antifreeze needs
to be added.
Once added, to mix the antifreeze around the ground arrays thoroughly, it is advised that the ground array
circulation pump is turned on before the compressor is turned on. This ground array circulation pump
should be left running for two to three hours to ensure the antifreeze is mixed in all the ground arrays and
the heat pump.
Water should not be left in the ground array without biocide or antifreeze.
Plant Room Heat Pump Manual Version 11.1
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